1. Cross-Related Applications
This application claims priority from Chinese Patent Application Serial Nos. 200410029945.2 filed Apr. 6, 2004 and 200410086705.6 filed Oct. 29, 2004, the disclosures of which are incorporated herein by reference.
2. Background Art
It is known to conduct or distribute air either in natural flow or mechanical flow in order to ventilate rooms of a building. It is also known to conduct or distribute light, as daylight or artificial light, for instance, to use daylight for illuminating large rooms.
A light-pipe is simply an empty tube along which light can travel into the interior of a building or other dark spaces. A coating on the internal surface of the light-pipe is composed of highly reflective material, which has reflectance greater than 95%. The light-pipe uses the principle of high efficiency reflection to transmit the light to the other end. Research on light-pipes started in 1880 in Russia, but they weren't put into mass production until 100 years later. At that time, the internal coating reflectivity was around 0.85. At the end of 1970s, a Canadian scholar put forward a method using the isosceles triangle prism with apex angle 90 as the film. The transmission efficiency was highly improved but costs were too great. Nowadays, the majority of commercially available light-pipe films are from 3M company and their film thickness is only 0.5mm.
The integration of light-pipe and ventilation technology is an original innovation in the light-pipe technology field. It can provide not only illumination but also ventilation, thus to improve the fresh air in buildings. U.S. Pat. No. 6,141,645 disclosed a skylight system which includes a skylight opening, a ventilator opening and an artificial lighting fixture at the roof of a room. Through three separate systems, it can realize the sun lighting, ventilation and the artificial lighting simultaneously. But this system is too large and complex.
In addition, U.S. Pat. No. 5,988,843 discloses a method and device for conducting/distributing air and light, particularly in a building or the like. The air and light are conducted along the same transport path. It also has an artificial lighting fixture in the light-pipe. Although this invention is structural simpler than that disclosed in U.S. Pat. No. 6,141,645, the light and air are conducted along the same transport path. Thus, after a considerable period of time, the dust will deposit in the duct, which will surely affect the transmission efficiency of light. So, it needs routine cleaning and thus increases maintenance cost.
There are no known reports about a light-pipe system integrated with photocatalytic air purification and ventilation. This invention not only can realize lighting and ventilation, but also can purify the indoor air. At the same time, the structural design of the light-pipe system is simple, can be easily installed and doesn't need periodic maintenance.